arch/mn10300/mm/cache-flush-icache.c

   1 /* Flush dcache and invalidate icache when the dcache is in writeback mode
   2  *
   3  * Copyright (C) 2010 Red Hat, Inc. All Rights Reserved.
   4  * Written by David Howells (dhowells@redhat.com)
   5  *
   6  * This program is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU General Public Licence
   8  * as published by the Free Software Foundation; either version
   9  * 2 of the Licence, or (at your option) any later version.
  10  */
  11 #include <linux/module.h>
  12 #include <linux/mm.h>
  13 #include <asm/cacheflush.h>
  14 #include <asm/smp.h>
  15 #include "cache-smp.h"
  16
  17 /**
  18  * flush_icache_page - Flush a page from the dcache and invalidate the icache
  19  * @vma: The VMA the page is part of.
  20  * @page: The page to be flushed.
  21  *
  22  * Write a page back from the dcache and invalidate the icache so that we can
  23  * run code from it that we've just written into it
  24  */
  25 void flush_icache_page(struct vm_area_struct *vma, struct page *page)
  26 {
  27         unsigned long start = page_to_phys(page);
  28         unsigned long flags;
  29
  30         flags = smp_lock_cache();
  31
  32         mn10300_local_dcache_flush_page(start);
  33         mn10300_local_icache_inv_page(start);
  34
  35         smp_cache_call(SMP_IDCACHE_INV_FLUSH_RANGE, start, start + PAGE_SIZE);
  36         smp_unlock_cache(flags);
  37 }
  38 EXPORT_SYMBOL(flush_icache_page);
  39
  40 /**
  41  * flush_icache_page_range - Flush dcache and invalidate icache for part of a
  42  *                              single page
  43  * @start: The starting virtual address of the page part.
  44  * @end: The ending virtual address of the page part.
  45  *
  46  * Flush the dcache and invalidate the icache for part of a single page, as
  47  * determined by the virtual addresses given.  The page must be in the paged
  48  * area.
  49  */
  50 static void flush_icache_page_range(unsigned long start, unsigned long end)
  51 {
  52         unsigned long addr, size, off;
  53         struct page *page;
  54         pgd_t *pgd;
  55         pud_t *pud;
  56         pmd_t *pmd;
  57         pte_t *ppte, pte;
  58
  59         /* work out how much of the page to flush */
  60         off = start & ~PAGE_MASK;
  61         size = end - start;
  62
  63         /* get the physical address the page is mapped to from the page
  64          * tables */
  65         pgd = pgd_offset(current->mm, start);
  66         if (!pgd || !pgd_val(*pgd))
  67                 return;
  68
  69         pud = pud_offset(pgd, start);
  70         if (!pud || !pud_val(*pud))
  71                 return;
  72
  73         pmd = pmd_offset(pud, start);
  74         if (!pmd || !pmd_val(*pmd))
  75                 return;
  76
  77         ppte = pte_offset_map(pmd, start);
  78         if (!ppte)
  79                 return;
  80         pte = *ppte;
  81         pte_unmap(ppte);
  82
  83         if (pte_none(pte))
  84                 return;
  85
  86         page = pte_page(pte);
  87         if (!page)
  88                 return;
  89
  90         addr = page_to_phys(page);
  91
  92         /* flush the dcache and invalidate the icache coverage on that
  93          * region */
  94         mn10300_local_dcache_flush_range2(addr + off, size);
  95         mn10300_local_icache_inv_range2(addr + off, size);
  96         smp_cache_call(SMP_IDCACHE_INV_FLUSH_RANGE, start, end);
  97 }
  98
  99 /**
 100  * flush_icache_range - Globally flush dcache and invalidate icache for region
 101  * @start: The starting virtual address of the region.
 102  * @end: The ending virtual address of the region.
 103  *
 104  * This is used by the kernel to globally flush some code it has just written
 105  * from the dcache back to RAM and then to globally invalidate the icache over
 106  * that region so that that code can be run on all CPUs in the system.
 107  */
 108 void flush_icache_range(unsigned long start, unsigned long end)
 109 {
 110         unsigned long start_page, end_page;
 111         unsigned long flags;
 112
 113         flags = smp_lock_cache();
 114
 115         if (end > 0x80000000UL) {
 116                 /* addresses above 0xa0000000 do not go through the cache */
 117                 if (end > 0xa0000000UL) {
 118                         end = 0xa0000000UL;
 119                         if (start >= end)
 120                                 goto done;
 121                 }
 122
 123                 /* kernel addresses between 0x80000000 and 0x9fffffff do not
 124                  * require page tables, so we just map such addresses
 125                  * directly */
 126                 start_page = (start >= 0x80000000UL) ? start : 0x80000000UL;
 127                 mn10300_local_dcache_flush_range(start_page, end);
 128                 mn10300_local_icache_inv_range(start_page, end);
 129                 smp_cache_call(SMP_IDCACHE_INV_FLUSH_RANGE, start_page, end);
 130                 if (start_page == start)
 131                         goto done;
 132                 end = start_page;
 133         }
 134
 135         start_page = start & PAGE_MASK;
 136         end_page = (end - 1) & PAGE_MASK;
 137
 138         if (start_page == end_page) {
 139                 /* the first and last bytes are on the same page */
 140                 flush_icache_page_range(start, end);
 141         } else if (start_page + 1 == end_page) {
 142                 /* split over two virtually contiguous pages */
 143                 flush_icache_page_range(start, end_page);
 144                 flush_icache_page_range(end_page, end);
 145         } else {
 146                 /* more than 2 pages; just flush the entire cache */
 147                 mn10300_dcache_flush();
 148                 mn10300_icache_inv();
 149                 smp_cache_call(SMP_IDCACHE_INV_FLUSH, 0, 0);
 150         }
 151
 152 done:
 153         smp_unlock_cache(flags);
 154 }
 155 EXPORT_SYMBOL(flush_icache_range);